I bought some Trimec lawn and weed killer from Tractor supply co and applied it at 1 OZ per gallon of water and it has done almost noting to the weeds. My sprayer is spraying .5 gallon of water per thousand square feet and according to the label im spaying over the recommended rate. Is my mix rate off or is this stuff not that good or is it the temps. I was trying to kill dandelion and some clover its been 5 days since i sprayed and the temps have been High 50s in the day and almost freezing at night. Thanks